Image analysis – Applications – Target tracking or detecting
Reexamination Certificate
1996-09-17
2001-06-19
Couso, Jose L. (Department: 2621)
Image analysis
Applications
Target tracking or detecting
C342S045000
Reexamination Certificate
active
06249589
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a device for passive friend-or-foe discrimination of targets, in particular of airborne targets, wherein the target to be identified is observed by means of a video camera.
Modern fighter aircraft or anti-aircraft batteries have target-tracking missiles which permit fighting enemy aircraft already from large distance. The distances to the aircraft to be fought at the moment of firing the target-tracking missile may be so large that the targets cannot be identified unambiguously. Therefore, the risk exists that erroneously a “friendly” aircraft is fought.
In order to avoid erroneous killing of the wrong aircraft, “IFF”-apparatus (identification friend or foe) are known. Such an IFF-apparatus transmits challenging signals, which “ask” the target aircraft, whether it is a friend. If the aircraft is a friend and has a corresponding IFF-apparatus, it understands this inquiry. It will then transmit a coded answer that it is “friendly”. The IFF-apparatus may operate with radio waves, RADAR or laser.
These IFF-apparatus suffer from the disadvantage that the challenged aircraft has to have a corresponding response apparatus. Usually, the correct answers are changed daily. This presents problems with multi-national formations. A further disadvantage is that it is an active procedure: A challenging signal is transmitted. By this challenging signal, the challenger declares himself to a possible enemy.
Passive identification apparatus for friend-or-foe discrimination are known for two-seater combat aircraft, these apparatus operating with a video camera. By means of the video camera, a highly magnified image of the target is generated on a monitor for the view of the fighter observer. This permits identification ranges of about 20 km to be reached. Problems result from the fact, that the image is not stable due to vibrations of the aircraft. The fighter observer has to concentrate on the image during rather long time, in order to safely identify the target.
SUMMARY OF THE INVENTION
It is the object of the invention to improve the friend-or-foe discrimination of targets, in particular of airborne targets, carried out by means of a video camera.
According to the invention this object is achieved in an apparatus as defined in the beginning in that the video camera is mounted for rotation about two axes and is arranged to be aligned with a target by a servo device controlled by radiation from the target.
With such an assembly, the video camera is aligned with the target with the aid of target radiation, i.e. of radiation which is emitted or reflected by the target. The video camera is rotatable about two axes. Thereby, the alignment with the target can be de-coupled from the movements of the carrier, i.e. in particular of a fighter aircraft, and can be maintained pointing towards the target.
The target radiation can be detected by a missile seeker head which serves to control the servo or follow-up device. The missile seeker head is aligned, anyhow, with the target to be fought and tracks this target. The signals obtained thereby can, in parallel thereto, cause the alignment of the identification apparatus.
The target radiation may also be RADAR radiation which is reflected by the target. It is then possible to make use of the RADAR, conventionally present in fighter aircraft, to align the video camera.
It is, however, also possible to detect the target radiation by means of the video camera itself and to control the servo device by control signals obtained by image processing of the video image. Then the video camera aligns itself with the target on the basis of the image detected by the camera itself.
In order to avoid disturbances due to the self-movements of the fighter aircraft, the video camera may be mounted on an inertially stabilized platform. The stabilized platform is rotated by control signals to align the camera with the target independently of movements of the fighter aircraft. To this end, the control signals may, for example, be applied to torqers of stabilizing gyros.
For the identification of the target, the target detected by the video camera may be imaged on the screen of a monitor. Transformation signals obtained by image processing may be used to keep the image of the target on the monitor substantially stationary in the center of the screen. This permits undisturbed observation and identification of the target.
In order to permit, on one hand, detection of a target within a relatively large solid angle and, on the other hand, to permit identification of the target at high magnification and resolution, the video camera may have a zoom objective, which, during the target detection phase, is adjusted to provide a relatively short focal length and, after target detection and alignment of the optical axis of the video camera with the target, is adjusted to provide a relatively long focal length and a correspondingly larger magnification.
Advantageous are image processing means for enhancing the contrast of the target image relative to its background. Image processing means can be provided for automatic evaluation of the image of the target received from the video camera can be provided to recognize friendly or enemy targets.
An embodiment of the invention is described in greater detail hereinbelow with reference to the accompanying drawings.
REFERENCES:
patent: 3742812 (1973-07-01), Woodworth et al.
patent: 3794761 (1974-02-01), Genchi et al.
patent: 3879637 (1975-04-01), Woodworth
patent: 3934250 (1976-01-01), Martin, Jr.
patent: 4034208 (1977-07-01), Vaeth et al.
patent: 4086841 (1978-05-01), MacDonald
patent: 4316218 (1982-02-01), Gay
patent: 4418993 (1983-12-01), Lipton
patent: 4550435 (1985-10-01), Hayman
patent: 4688092 (1987-08-01), Kamel et al.
patent: 4778268 (1988-10-01), Randle
patent: 4843459 (1989-06-01), Perrin et al.
patent: 4942538 (1990-07-01), Yuan et al.
patent: 5001348 (1991-03-01), Dirscherl et al.
patent: 5123327 (1992-06-01), Alston et al.
patent: 5197691 (1993-03-01), Amon et al.
patent: 5220361 (1993-06-01), Lehmer et al.
patent: 5227859 (1993-07-01), Leib et al.
patent: 5249035 (1993-09-01), Yamanaka
patent: 5347910 (1994-09-01), Avila et al.
patent: 5471541 (1995-11-01), Burtnyk et al.
patent: 5481483 (1996-01-01), Ebenstein
patent: 5483865 (1996-01-01), Brunand
patent: 5515301 (1996-05-01), Corby, Jr. et al.
patent: 5566246 (1996-10-01), Rao
patent: 5592563 (1997-01-01), Zahavi
patent: 5606627 (1997-02-01), Kuo
patent: 5751830 (1998-05-01), Hutchinson
patent: 5822713 (1998-10-01), Profeta
patent: 3432892 (1986-03-01), None
patent: 3435634 (1986-04-01), None
patent: 2242590 (1991-10-01), None
Bodenseewerk Geratetechnik GmbH
Couso Jose L.
Dang Duy M.
Mallinckrodt Robert R.
Mallinckrodt & Mallinckrodt
LandOfFree
Device for passive friend-or-foe discrimination does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Device for passive friend-or-foe discrimination, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Device for passive friend-or-foe discrimination will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2475415